世界首款高压谐振控制／驱动器L6598

ST公司不久前推出的高压谐振控制器L6598,是目前世界首款将谐振变换器和600V的高压半桥驱动器集成于同一芯片上的IC。L6598采用BCD(双极-CMOS-DMOS)离线(OffLine)技术制造,适用于带谐振拓朴结构的AC/DC适配器、DC/DC模块和CTV及监视器等高效电源中,可取代以往由两个芯片组成的半桥谐振器,从而减小了元件数量和PCB尺寸。L6598也可替代单端谐振变换器,以提高变换器性能。     

高性能集成电源管理芯片

该款芯片内部集成了AC适配器／USB双源锂电池线性充电器、可动态配置输出电压的两路高效降压型DC／DC转换器、一路低压差线性稳压器、电池监测电路以及I^2C通信接口。SD49142内置的充电器可通过控制外部开关并按照优先级来选择适配器,或者USB这两种供电路径对一节锂电池进行线性充电。     

光电子技术

0101904能有效简化电源设计的高压谐振控制器 L6598[刊]/蒋孝平//国外电子元器件.—2000,(11).—19～21(C)L6598是一款将谐振变换器与600V 的高压半桥驱动器集成于同一芯片的控制 IC,可取代单端谐振变换器和多芯片解决方案,从而可有效地减少元器件数量,简化高效电源设计。文章介绍了 L6598的内部结构、特点、功能、原理及其应用电路。0101905紫外光源的空间相干性对光纤光栅写入的影响[刊]/谢增华//压电与声光.—2000.22(5).—288～290(L)对相位掩膜法紫外写入光纤光栅技术中紫外光源     

交流适配器/电池供电系统的电源管理方案

便携式产品通常由交流(AC)适配器或电池提供系统电源,图1所示电路能够自动切换AC适配器和电池输入,为系统提供稳定的5V和3.3V输出,通过限制不必要的能量损耗有效延长电池寿命。该电路仅在撤掉AC适配器时吸取电池能量,适配器与电池输入之间输出电流达600mA;线性稳压器提供3.3V输出、电流达200mA。 图中IC1内部包括一路开关型稳压器和一路线性稳压器,独立的ON/OFF控制能够在开关型稳压器关闭时保持线性稳压器输出有效,此时,线性稳压器输入电压由IC2提供。IC2为开关型DC—DC转换器,能够将不稳定的AC适配器输入     

便携式媒体播放器电源管理方案

MAX8819A集成了3路2MHz降压转换器和一路具有串行步调亮度控制的28V升压转换器,用于驱动2～6个WLED,在整个负载范围内效率高达95％。其智能电源选择器电路控制电池、USB／ACDC适配器和系统负载之间的电源分配。当连接USB或AC／DC适配器时,系统负载没有用到的那部分输入电源对电池充电。     

汽车灯控电路1041测试包的设计

汽车灯控集成电路1041的测试包设计一反常规,采用了全DC测试方法,实现了电路的全部功能检查、DC参数以及AC参数的测试。最大限度地缩短了电路的检测时间,简化了测试适配器的设计和制造,大大降低了电路的测试成本。本文着重介绍了1041的AC参数测试原理、方法,以及实现其交流参数测试的硬件和软件设计。     

隔离式DC／AC变换电路的设计及应用

本文给出了两种常见的DC／AC变换电路,从原理上分析了它们的特点,指出了它们在应用方面的局限。在此基础上阐述了一种能带大感性负载的隔离式DC／AC变换电路的原理,并介绍了关键部件的设计过程。     

飞利浦170B LCD显示器供电电源

液晶显示器的电源系统与CRT显示器有根本的区别,由于LCD显示器体积、功耗较小,其供电电源既可取自AC市电也可取自可充电池。所以LCD显示器电源部分的主体是DC/DC变换器,其功能是将单一电压的可充电池变换为各功能电路需要的电压。交流适配器的用途是将AC市电变成与供电电池电压相近的直流输出,以在固定场所使用显示器时可直接由市电供电。不过该交流适配器不同于笔记本电脑交流适配器,它设在     

基于交错Boost变流器和LLC谐振变流器的高效率车载充电机

载充电机(OBC)是电动汽车(EV)的关键部分,为EV提供充电通道。OBC的前级AC/DC电路采用交错Boost电路进行功率因数校正、控制直流母线电压。后级DC/DC采用隔离型全桥LLC电路对充电电压和充电功率进行控制。对交错Boost变流器的效率进行计算,并对LLC谐振变流器的效率进行优化。开发一台3.3 kW OBC样机,其整机效率高达94.9%,功率因数超过99.5%。交错Boost变流器和LLC谐振变流器的效率分别达到97.7%和97.6%,OBC的功率密度可达1.05 kW/L。     

松下M7摄像机故障检修两例

例1 故障现象:重放时,图像、声音均无,其它功能正常。分析检修:该机是通过AC适配器把视频、音频信号调制成RF信号。监测AV输出的视频/音频信号,始终正常。故而怀疑故障出在AC适配器,检测整个AC适配器电路没发现故障,分析该部分电路得知:该电路由AC适配器-AV接口电路、RF变换器组成。AV接口电路用于对摄像机送出的视频信号进行缓冲     

基于ATmega16L的便携设备电源系统设计

为满足目前便携设备对电源系统的需求,提出一种基于微控制器为控制核心的便携设备电源系统方案,利用高性能、低功耗的ATmega16L微控制器作为检测和控制核心,配以电池充放电电路、DC/DC变换电路、外部适配器和锂电池组等,实现了灵活性高、功能完备的电源系统。     

DC voltage sensorless single-phase PFC converter

We propose a simple DC voltage sensorless single phase PFC converter by detecting an AC line voltage waveform. Both DC voltage and AC current sensors used in the conventional PFC converter are not required to construct the control system. The conventional converter circuit with a boost chopper circuit in the DC side from a rectifier circuit is used as the main PFC converter circuit. In the control system, the circuit parameters such as a series inductance L and equivalent load resistance value R/sub d/ are used to generate the sinusoidal current waveform. The DC voltage is directly controlled by the command input signal k/sub d/(=E/sub d//E/sub a/) for the boost chopper circuit. The DC voltage regulation is small because of the feed forward control for the AC line voltage E/sub a/ and no dependence of the circuit parameters. The sinusoidal current waveform in phase with the AC line voltage can be obtained. The feasibility of the proposed control system is verified by some simulation and experimental results.     

Asymmetrical pulse-width-modulated resonant DC/DC convertertopologies

This paper presents asymmetrical pulse-width-modulated (APWM) DC/DC resonant converter topologies that exhibit near-zero switching losses while operating at constant and very high frequencies. The converters include a bridged chopper to convert the DC input voltage to a high-frequency unidirectional AC voltage, which in turn is fed to a high-frequency transformer through a resonant circuit. The bridged chopper has two switches that alternately conduct. The duty cycles of the conduction of the switches are complementary with one another and are varied to control the output voltage. Three resonant circuit configurations suitable for this type of control are presented. Frequency domain analysis of the converter is given, and performance characteristics are presented. Experimental results for a 48-5 V, 30 W converter show an efficiency of 88% at a constant operating frequency of 1 MHz     

A unity power factor PWM rectifier with DC ripple compensation

This paper presents a new topology for a pulsewidth modulation (PWM) rectifier which achieves unity power factor on the AC supply side and ripple reduction on the DC output side. The main circuit of this rectifier consists of a conventional PWM rectifier and a pair of additional switches. The switches and PWM rectifier are controlled such that the ripple current on the DC line is reduced, and unity power factor is achieved on the AC line. As a result, this circuit does not require a large DC capacitor or a passive LC resonant circuit. Furthermore, control of the additional switches and PWM rectifier requires only a simple control circuit. The effectiveness of this circuit was confirmed by experiments and analysis. The rectifier is useful for uninterruptible power systems (UPSs) and DC power supplies, especially for cases in which batteries are connected to the DC line     

无直流电压传感器的单相APFC变换器

文章对一种只检测交流输入电压而不需要检测输出直流电压的简化单相PFC变换器进行了理论分析和研究。在构建控制电路时,不需要常规PFC变换器中的输出电压传感器和输入电流传感器。PFC变换器的主电路为整流电路的直流侧接一级Boost电路。在控制电路中,使用电感L、等效负载电阻Rd等电路参数产生正弦电流波形基准,输出电压直接由控制量Kd(=Ed/Ea)来调节。通过控制,可以得到恒定的直流输出电压和与交流输入电压同相位的正弦电流波形。仿真结果证明了该变换器的可行性。     

基于高频高压交流母线多组输出直流电源的研制

本电源是基于高频高压交流母线具有多组输出的直流电源，它具有高达200kHz的开关频率，后级的整流电路由于高频交流母线的存在，使得变压器和电感的设计变得简单，滤波电容的选择也更容易。本电源由PFC电路提供400V的高压直流输入，再由MOSFET组成全桥逆变电路，在固定额率的PWM发生电路和IR2110 MOSFET驱动电路作用下，只加—个谐振电感就可实现开关管的零电压开通，可在大大降低开关损耗和噪声的同时实现直流交流的变换。整流部分采用倍流整流电路以提高原边电压的利用率，可输出低压大电流。由于采用肖特基管，—方面可使得二板管的损耗可以接受，另外—方面还避免了采用同步整流电路所面临的电路结构复杂和驱动困难。     

Phasor-Domain Modeling of Resonant Inverters for High-Frequency AC Power Distribution Systems

The circuit modeling and analysis of resonant inverters is complex because the state variables such as inductor currents and capacitor voltages are AC dominant. The phasor dynamic modeling method maps the periodical time-varying state variables into stationary frame for each harmonic of interest. Correspondingly, the circuit is decomposed into two DC subcircuits, the state variables of which are the time-varying Fourier coefficients of the original AC variables. A small-signal model can be derived by applying small perturbation and linearization to the Fourier coefficients. A phasor-domain modeling method is used to investigate the resonant inverters in high-frequency AC power distribution systems. A resonant inverter system with five energy storage elements is modeled and simulated, and compared with switch simulation for both steady state and transients. The phasor model simulation matches the switch model simulation in both steady state and transients, but takes much less computing time. In addition, this model closely relates to the power converter topology in time domain, and therefore, keeps the physical meaning of the state variables. It can be used for high accuracy of modeling, simulation, and circuit analysis and control design. It can be extended to a higher order of resonant topologies including parasitic components. A high-frequency AC system with two pulse-phase-modulation-controlled resonant inverters is modeled and simulated, and the current distribution control is investigated with the phasor model. The model simulation is compared with switch-level simulation and experimental results.     

A soft-switched, high-frequency resonant rectifier andcharacteristics of the controlled system

In this paper, a high frequency and soft-switched AC/DC rectifier employing a series-type resonant circuit is proposed to obtain the sinusoidal AC line current. Using the proposed rectifier, the high power factor and low harmonic currents are obtained in the AC line. Furthermore, several advantages such as the high power density and wide output voltage range can also be available. To regulate the output voltage of the proposed circuit, the digital proportional-integral (PI) controller is used whose sampling time corresponds to the zero-crossing point of the AC line voltage. Including this controller, the model for the closed-loop system is developed in order to examine the stability and dynamic characteristics. With this model, the gain of the PI-controller is determined by the pole assignment technique and the closed-loop dynamics is investigated by the root locus plots. A good agreement is made between the simulated and experimental results     

A study of series-resonant DC/AC inverter

A new DC/AC inversion for achieving an AC sinusoidal waveform synthesized by a series of quasi-sinusoidal pulses is described. A modified pulse-width-modulated (PWM) controller is presented for driving the power switch to operate in a forced discontinuous-conduction mode (FDCM) so as to achieve series-resonance in the power stage. The output power results mainly from the energy stored in the resonant capacitor and is independent of the number of the resonant quasisinusoidal pulses. Three dynamic conversion states including charging, resonant, and RC-discharging states are modeled and analyzed. Signal analysis for the composite AC sinusoidal waveform is conducted. A small-signal model for system performance investigation is described. A prototype of a 1 kW DC/AC inverter is examined by simulation and experimentation in order to assess the system performance